Propeller for helicopters



Oct.'4, 1932. w. P. VAN L AMMEREN LSZ PROPELLER FOR HELICOPTERS Filed Nov. 27, 195o 2 sneetsneet 1 Oct 4 1932. w. P. VAN LAMMEREN 1,880,302

PROPELLER FOR HELICOPTERS Filed Nov. 27. 195o 2 shets-shee 2 Patented Oct. 4, 1932 WILLEM :PETRUS VAN LAMMEREN, or vooRscHoTEN,NETHERLANDS PROPELLER FOR HELICOPTERS Application iled November 27, 1930, Serial No. 498,518, and in Great Britain December 3, 1929.

This invention relates to propellers of the type comprising symmetrical blades or Wings rotatably mounted on axes disposed around a common axis about Which the rotary propeller isA rotatable as a unit.

One object of the present invention is to provide means for featheringthe blades or Wings during the rotating of the propeller for effective driving purposes in a single direction.

According to the present invention the propellers are each provided with one ork more symmetrically shaped blades or Wings and with means forfeathering the blade to give the same a positive angle of incidence, which increases from Zero to a right angle duringl one-half of the rotation of the propeller, and

during the other half of the rotation there is a negative angle of incidence which decreases from a right angle to Zero. The increase may be from an angle slightly more or less thanV OO to an angle of more or less than 90.

In order to best carry out the feathering movement, it is necessary to impart a vary ing angular movement to each blade relative to the uniform movement of the rotary propeller. Moreover, if the rotating of the propeller is in a clockwise direction, the'rotation of the blades should be in an anti-clock- Wise direction and vice-versa.

Another object of this inventionis to provide a means whereby the variation of the positive and negative angles ofincidence of' the blades maybe changed.: For example, the angles may increase or Vdecrease more or less rapidly in the first part of their respective half revolutions than in the latter partl thereof; v

More specifically my invention has for its object the provision of means Which will impart a small reverse movement to each blade during its stroke in the direction in which the propeller moves bof ily, or is to be moved,

peller as a Whole is bodily movable in theV direction in which thelielicopter moves, or is adapted to be moved under the influence of the propeller. During the stroke of the blade in the direction opposite to the aforesaid direction of bodily movement of the pro- -k peller, a comparatively large reverse movement is imparted to the blade corresponding to the amount of movement required in order lto keep the blade at right angles or substantially at right angles to the said direction Vof.

bodily movement.

Another objectof this invention is to make the propellerblades symmetrical in vieW of the fact that each bladerotates 180 about its ovvn axis during one complete rotation of the propeller. i

Still another object of this invention is to provide a cam operating on an eccentric rod and gearing to rotate the blades about their oWn axes during the rotation of the propeller about its axis. Preferably the cam comprises a plurality of portions having different crosssections, the various portionsmerglng into each otherto form a unitary cam. At one point along the cam the same is substantially circular in crossesection, but the portions on each side of the portion having a circular cross-section are elliptical in shape, and the ellipses on opposite sides of the portion havinga circular section, have their major axes at right angles to each other.

Mechanism is provided for shifting th cam to present different portions of the cam surface to the eccentric rods which, together'y with the gearing, rotate the blades. i My invention also contemplates moving a cam about its axis, eithersimultaneously with the movement in the direction of its axis, or independ-V ently of that movement. This arrangement enables meto vary the direction of the driving force exerted upon thepropeller by the helicopter or like machiney to` which it is fitted. 'l .n

Otherobjects of this invention Will appear hereinafter as the description thereof proceeds, the novel features and combinations being set forth in theappended claims.

In the dravvings- F ig. l represents an elevational view of a propeller for a helicopter or like device em-A bodying my invention, ,the view being taken.

coiA

substantially along the line 1 1 of Fig. 2;

Fig. 2 is a cross-section taken along the line 2-2 of Fig. 1';

Fig. 3 is a view similar to Fig. 1 showing a modified arrangement for my device;

Figs. 4vand 5 are fragmentary views of portions of the mechanism shown in Figs. 1 and 2, but show the partsvin a position of adjustment slightly different than that illustrated in Figs. 1 and 2; and Y I Fig. 6 is laY view looking in the direction 6-6 of Fig. 1. Y

The reference numeral 1 indicates the fuselage `of a helicopter orY like. device to which my invention is to be applied, it being understood that generally speaking there will beat least two units such as illustrated inthe drawings, one oneach side of the fuselage. This arrangement is shown clearly in Fig. 3of my Patent No. 1,772,119 granted August 15,1930. v I

A tube'2 mounted in a bearing 3of .the fuselage has an eccentric bearing ,4 therein adapted to rotatably support the main driving shaft 5 upon which the vpropeller blades of the helicopter are carried; i

The shaft 5 supports the framework 6- which comprises inner and outer ringsy 7 and 8 and radial struts 9. There are two frameworks 6, each of which is in effect a Wheel with six spokes 9, a hub portion 7 and a rim portion 8. The frameworks 6 are spaced from each other by a tubular member 10, and

rivets 11 or like fastening means pass. through the hub portions 7 and flanges on the ends of the tube 10 through thebearing members 12 to clamp they frameworks 6 in adjusted position relatively to each other. Pins 13 pass through the tub-e 10 and bearing members 12, and also through the shaft 5 to cause the frameworks 6 to rotate in unison with the shaft 5. i Any suitable mechanism may be used to rotate the shaft 5. Shafts 14 are rotatably mounted in bearings 15 and 16 on the frameworks 6, and propeller blades 17 are symmetrically arranged 'on the shafts 14 and are secured thereto by fastening means such as the rivets 18 orthe like.`

The blades 17 are symmetrical with'respect to the shafts 14, both in shape andV in the amount of each blade which entends on either side of the shaft. This is for a purpose which will appear later;

r`To one end 'ofeach ofthe shafts 14, I secure a gear 19. @ne end of a link 2O is rotatably mounted on the shaft'14 lbetween two nuts 15 as illustrated in Fig. 6, The other end of the link 2O rotatably receives the short shaft 21 to which is secured a pinion 22 which i is one-half the diameter of the gear 19.

Rotatably mounted. upon the tube2, is a circular plate 23. Links pivoted vtothe arms 9 and to the circular plate 23 constrain vthe `frameworks 6 and plate 2-3 to rotate in unison with each other although 'about different a-Xes. Upon the plate 23 are mounted the arms 24 and 25 which extend in a direction substantially parallel of the aXis of the tube 2. Each of the arms 24 and 25 has openings therein at the outer ends thereof acting as bearings for the slidable rods 26. Each slidable rod is provided with a roller 27 rotatablyl mounted on its inner end, and each of the rods is secured by means of a pin 28 to the shaft 21. made in two sections pivoted together at 29 so as to permit a certain amount of lateral movement of the outer end of the rod, and fora purpose which will appear later. Y

Springs 30 surround the rods 26, and are arranged within the openings 31 which are provided in the outer ends of the arms 25. Each of the vsprings 30 .abutsagainst that portion of the armv 25 which forms a bearing for the rod 26. The other end of each spring abuts against a collar 32 secured tothe rod 26ab0ut' which the spring is arranged.

On the tube 2 is mounted a cam member 33. This cam member has a bearing surface 34 which lits the outer surface of the tube 2, and a cam surface 35 which has the following shape: The central portion or the portion substantially at the center of the cam surface 35 is circular in cross-section as indicated by the dotted line 36in Fig. 1. The cam surface is adapted to be engaged byv the rollers 27 and control the positions of the rods 26.

The cam changes its shape towards the opposite ends thereof, the opposite end portions being ellipses, with the major axes of the ellipses on opposite sides of the central portion 36, at right angles to each other. The various sections of the cam merge into each other so as to form a continuous surface on the cam thereby enabling the cam to be shifted longitudinally of its axis while the propeller is in action. Y

.Preferably, but not necessarily, l provide means for rotating the cam about the tube 2 at the same time that ly shift the cam longitudinally of its axis. This means comprises a spline 37 on the tube 2, and a corresponding groove in the bearing portion 34 Vof the cam as was best illustrated in Fig.'2. The spline is substantially helical in shape, thereby causing the cam to rotate about the tube 2 when the cam is shifted:longitudinally of the tube, or if the cam is rotated, then the spline will cause a longitudinal movement'of the cam along the tube.

In order to shift the cam, I secure a collar 38 to one end of the cam. This collar is provided with an arm 39, having a laterally extending rod 40 extending through an arcuate slot 41 in the fuselage. An arm 42 having a forked end 43 straddling the rod 40, is pivoted at 44 to the fuselage, and is operated by means of the handle 45 or the like. The rocking of thearm 42 causes a corresponding rocking movement in a reverse di- The rods 26 are preferably 4 theV helix of the spline to cause the cam to rotion of the tate in the opposite direction.

The operation of my device is as follows:

The framework which supports the blades is caused to rotate by rotating the shaft 5, and the tube 2 is correspondingly rotated at the same speed as the'shaft 5. Y We will assume to begin with, that the cam is adjusted so that the rollers travel about the circular portion 36 thereof. Since the framework 23 has the same aXis as the axis of the cam, it

will be ssen that when the rollers travel along the portion 36 of the cam, that the rods 26 will not move inwardly or outwardly with respect to the a-Xis of the tube 2, as the springs 30 hold the rollers 27 in engagement with the cam at all times. The length of each link 20 is the same as the distance between the center of rotation of the sha-ft 5 andthe axis of the tube 2. v This arrangement causes the links which connect the blades to their respective rods, to Vremain parallel to each other `during the entire rotation of the propeller. As illustrated in Fig. Lithe` blade occupies a horizontal position when it is directly above the shaft 5, and has a 0 angle of incidence with the path through which its center of rotation travels, this path being a circle having its center at the center of the shaft 5. My invention contemplates having the angle of incidence approximately 45 when the blade reaches Vthe extreme left hand position of its travel when therollers are traveling over the circular portion `of the cam. The angle of incidence of the blades at their lowermost position is 90. This angle of incidence continuously changes from 0 to 90 and then from 90 back to 0 during the last half of the rotative movement of the propeller about the shaft 5 as is clearly illustrated in the drawings. During a complete rotation of the propeller, each blade rotates 90 about its own axis thereby necessitating the symmetrical arrangement of the blades described previously, as the second revolu- V blades is exactly the same as the first.

`With this arrangement, it will be seen that the rotation of the propeller causes the propelling of the helicopter or otherdevice in a direction toward the left.l A reversev rotation of the propeller unit causes a movement of the helicopter to the right.

When the cam is shifted so as tok move the same longitudinally of the shaft in a downward direction as viewed in Fig. 2, theJ- large ellipticalrportion 46 ofthe cam is brought into alignment with rollers so that when the blades are at the eXtreme left handV position, the rollersy are moved outwardly against the action of the springs in the manner illustrated in Fig. 5, thereby increasing the angle A to more than 45. when the cam is shifted kin the oppositel direction, the smaller elliptical portion 47 is brought into alignment with the rollers and when the blades ,are at the extreme left hand position, the angle A is less Ithan 45 as is illustrated in Fig. 4. Of course, it will be understood that there is a gradual increase of the angle of incidence from the uppermost position to the extreme left hand position, and that thereafter there is an increaserin the angle of incidence to the lowermost position.V lf the camis merely shifted longitudinally and is not rotated by a spline such as 37, then the angle of incidence at the top and at the bottom are the same as that illustrated in Fig. 3. kSince the cam at these points have their surfaces parallel to the axis of the tube 2, when the cam showny inv Similarly from the uppermost position of the blade.

Through the next of revolution,`the increase is relatively slow. Throughthe neXt 90 the increase is again very slow and gives in effect a negative angle of incidence.

Through the last 90 the change inthe angle of incidence is very rapid as in kthe first 90 Vof revolution.A This arrangement isv such that the angle is rapidly changing as the blade moves from right to left, but is changing slowly when movingfrom left to right.

The reverse is true when the cam shown in Fig. 2 is moved upwardly to bring the smaller elliptical portion into engagement with therollers 27. That is, there is al relatively slow change in the angle of incidence during the movement of the blade from right to left, and a relatively rapid change in the angle of incidence as the Iblade moves from left to right. Y i

When the rollersv contact with the larger elliptical portions of the cam, there is more of a tendency for the propeller to lift the helicopter than to movev it toward the left, whereas, whenthe rollers are in contact with the smaller Velliptical portions of the cam, there is more of a tendency to move the helicopter towardv the left and less tendency to` lift the same.

W'hen a spline is use d to cause rotation of the cam when the same is moved longitudinally, the result 1s that the angle of incidence at the top instead of being zero iseither a Cui tion of movement, while during the movement of the blade to the left, it is held at a decreasing angle of incidence and then atan increasing positive angle of incidence as it traverses its downward stroke. l

The arrangement shown in Fig. 3 is substantially the same asthat shown in Figs. 1 and 2, with the exception that the link corresponding to the link 20, carries an additional gear 48 which is rotatably mounted on the link 20 and meshes with the gears 19 and 22. This gear 4:8 acts as an idler gear. Itl will be understood that the ratio of the gears 19 and 22, is two to one, as in the embodiment shown in Figs. 1 and 2.

Obviously those skilled in the art to which this invention pertains may make various changes in the construction and arrangement of parts without departing from the spirit of this invention, and therefore I do not wish to limit myself except as hereinafter set forth in the claims. y

Havingthus fully described my invention,

what I desire to secure by LetterssPatent of the United States is: A

1. In a rotary propeller, the combination A with a rotary supporting member, blades ro li c tatable on said member, means forrotating each blade Yabout its own axis vthrough sub-Y stantially 90 as saidv member rotates about its axis through.substantially 180, means for rotating', said blades about their own axes another substantially 90 while said member Arotates through substantially another 180, and mechanism for varying the rate of rotation ofl said Vblades about vtheir own axes. p Y

2. In a rotary propeller, the combination with a rotary supporting member, blades rotatable on'said member, means for rotating each blade about itsown axis through substantially 90 as said member rotates about its axis through substantially 180, mea-ns for rotating said bladesv abouttheir own axes anothersubstantially 90 while said member rotates through substantially an-A other 180, and mechanism for varying the rate of rotation of saidblades about their own axes, so that said blades rota-te more rapidly in the first parts ofthe respective 180 movements. of saidmember thanv in the latter parts thereof. Y

3. In a propeller, the combination with a framework, of a plurality of blades rotatably mounted on said framework so as to rotate about parallel axes, shafts forming bearings p for said blades land rigid` therewith, said shafts being rotatable in bearings in said frame, a gear secured to each shaft, a second gear meshing with each of said first mentioned gears, links connectingthe pivots of each pair ofv said gears, rods pivoted to said linksI and secured to said second gears, a cam having elliptical and circularsurfaces thereon adapted to actuate said rods, and means for selectively moving'said cam to position one of said surfaces in operative engagement withsaid rods. l

1l. In a propeller,the combination with a shaft,'of.a framework on said shaft, a plurality of lparallel'shafts rotatablyl mounted on said framework, a blade' secured to each shaft,links rotatable on said shafts, gears secured to said shafts, a second gear rotatably mounted on each of said links and out of mesh with said first gear, idler gears meshing with both of said gears on each link, rods rigidly connected to each of said second mentioned gears, a cam for actuating said blades, and means for shifting said cam about its axis to change the time of rotation of said blades to various angular positions, said gears being controlled by movements of said cam to rotate said blades. 1

5. A device as set forth in claim 3 in which the rods rotate in unison with the blades but about a different axis, thereby causing rotation of said blades relative to said framework as said blades andV rods rotate and through the intermediary of said links.

' 6. A propellercomprising a member rotatable about an axis, a blade rotatablysupported by said member and rotatable about its own axis while bodily movable' with said member about the axis of rotation of said member, and mechanism for varying the angle of incidence of saidV blade relative to the path of travel of the axis of rotation of said blade comprising means for varying the angle of incidence of said blade from substantially zero degrees at one position to substantially 90 halfway along said path and for again changing the said angle back to substantially zero degrees during the movement of said blade along the last half of said path, said` mechanism including means for changing the rate of rotation of said blade about its own axis.

Y7. In a propeller, the combination with a frame-work rotatable upon a substantially horizontal axis, rotary blades carried by said frame-work and rotatable about axes substantially parallel to said first' axis, a cam, and gearing connecting said cam and blade to rotate said blade through substantially 90 about. its own `axis during substantially thefirst 180 of the rotation of saidv frame-work, and yfor rotatingv said blades another 90 about their axes during the next 180 of rotation of said framework, said cam having different operative surfaces thereon selectively cooperating with said gearing to vary the rate of rotation of said blades about their axes during each ofy said 90CJ of rotative movement about their own axes.

8. In a propeller, the combination with a framework, of a plurality of blades rotatable upon said frame-work about parallel axes, a cam and gearing operatively connecting each of said blades, said cam comprising a second gear meshing with the gear secured to said blade, rods to which said second gears are rigidly secured, and means for maintaining said gears in mesh with each other, the movement of said rods causing rotation of said blades through the intermediacy of said gears, said cam mechanism having a plurality Vof surfaces selectively movable to operative position to operate said rods selectively at different rates to thereby impart dilierent rates of movement of rctation to said blades.

9. In a propeller, the combination with a frame-work, of a plurality of blades rotatable upon said frame-work about parallel axes, a cam and gearing operatively connecting each of said blades, said cam comprising a second gear meshing with the gear secured to said blade, rods to which said second gears are rigidly secured, and means for selectively moving the desired cam surfaces into operative relation with said rods.

l0. In a propeller, the combination with a frame-work, of a plurality of blades rotatably mounted on said frame-work so as to rotate about parallel axes, shafts forming bearings for said blades and rigid therewith, said shafts being rotatable in bearings in said frame, a gear secured to each shaft, a second gear meshing with each of said first mentioned gears, links connecting the pivots of each pair of said gears, rods pivotedto said links and secured to said second gears, a cam havingrelliptical `and circular surfaces thereon adapted to actuate said rods, and means for moving said cam about its axis to vary the time at which the blades occupy given positions with respect to a fixed plane parallel to the axis of rotation thereof.

l1. In a propeller, the combination with a frame-work, of a plurality of blades rotatably mounted on said frame-work so as to rotate about parallel axes, shafts forming bearings for said blades and rigid therewith, said shafts being rotatable in bearings in said frame, a gear secured to each shaft, a second gear meshing with each of said first mentioned gears, links connecting the pivots of each pair of said gears, rods pivoted to said links and secured to said second gears, a cam having elliptical and circular surfaces thereon adapted to actuate said rods, and means for moving said cam to position different ones of the operative surfaces thereof in a position to actuate said rods and simultaneously change the angular position of said cam. v

12. In a helicopter, the combination with a blade carrying frame having a ixed axis of rotation, blades rotatably mounted on said frame, a cam having an axis of rotation substantially parallel to but spaced from the axis of rotation of said frame, a plurality of operating rods bodily movable about the axis of rotation of said frame for operating said blades and for rotating said blades about their axes of rotation as said blades revolve about the axis of rotation of said frame, said cam having surfaces spaced longitudinally of its axis being respectively in the shape of ellipses having their major axes at different angles with respect to each other, a circularl surface and intermediate surfaces gradually merging into one another, and means for shifting said cam longitudinally of its axis of rotation to position different cam surfaces in operative position to vary the rate of angular rota-tion of said blades about their axes.

In testimony whereof I have signed my name to this specification on this 17th day of November A. D. 1930.

WILLEM PETRUS VAN LAMMEREN. 

